The art of welding is used for many purposes, but often to fill holes that have been left in surfaces, for example screw holes or rivet holes left in sheet metal, such as on the side of a car or truck body.
When welding closed a hole in light gauge sheet metal with a wire feed welder, such as a MIG welder, the welding operator must start the weld at one side of the hole, and move around the perimeter of the hole, working towards the center.
This sort of welding often poses a problem, as the wire feed weld wire will often go through the hole, causing the welding operator to have to cut off the lead of the wire and start again with a fresh lead.
A further problem arises when the heat from the welding machine melts the sheet metal around the hole, making the hole larger, not smaller. Even if the hole is not made larger, the heat often distorts the sheet metal body panels, creating more problems to be fixed.
Another problem arises because the back surface of what is being welded accumulates a mound of metal from the weld built-up on the front and backside of the sheet metal panel. The excess welded material on the front side can usually be ground off, but the welded material that remains on the inside of a sheet metal body panel often is inaccessible to a grinder. This is especially true of the extra mirror holes that tend to accumulate on the sides of old truck doors.
While, a welding operator could try to have an assistant hold something on the other side of the hole being welded closed, this is not usually practical, as it doubles the labor cost, and often, such an extra person simply is not usually available.
Magnets have long been used to hold backup devices in place for welding, but most required bulky magnets with screw assemblies, e.g., U.S. Pat. No. 2,584,072 to White, and U.S. Pat. No. 2,866,889 to Dempsey. These old magnetic devices did not have a means for spacing the backup device away from the magnet to protect the magnet from the heat.
There are commercially available “plugweld pliers” that support the weld area, use copper alloy pads to absorb excess heat, and cover the back of the hole, as the weld is being applied. One such example of these plugweld pliers is sold by Eastwood Co. on its website at www.eastwoodco.com under the Auto Body; Body & Fender; Body Tools & Accessories section. Unfortunately, these types of plugweld pliers only work on areas that are within two inches of the edge of a sheet of metal, and on which the back end of the hole is readily accessible and exposed, to affix the plugweld pliers.
Also available from Eastwood Co. on its website at www.eastwoodco.com under the Auto Body; Body & Fender; Body Tools & Accessories section is a product known as a magnetic copper butt-weld backer set. These copper alloy plates have magnets to hold them to the back of a hole, which is good because the welding material does not stick to the copper alloy plate. Unfortunately, as noted in the Customer Reviews on the Eastwood Co. website, the magnets do not have enough holding power, and they lose their power due to repeated heating.
In order to address these and other issues, there remains a long felt need in the art for a magnetic plug weld tool that has sufficient magnetic power to hold onto metal, even in tight spaces, with spacing between the copper alloy plate, and that does not require that the hole to be plugged is within two inches of the edge of the sheet metal. The inventor has solved all of these problems with a tool that works and has experienced significant commercial success in the many months that it has been available for purchase by the welding public.